In line-scan scanning laser ophthalmoscopy (SLO) systems a line of light is used to illuminate a patient's retina at a variety of places, rather than a small spot as is used in a confocal SLO system. If the frequency of this line of light is to be adjustable, one solution would be to use separate lasers as the source of light and to select among the lasers. In fact this is what is done in some confocal SLO systems. However this provides only discrete frequencies of light, and the use of multiple lasers increases both the size and cost of the SLO system. Another solution would be to use a tunable laser. However while this would provide a more continuous selection of frequencies, the use of a tunable laser increases the cost of the SLO system even more.
There is a need to provide a line-scan SLO system which allows selection of a narrowband of wavelengths from a large range of wavelengths, without requiring the high cost of tunable lasers.